1. Field of the Invention
The invention relates to a receiver system for a Fresnel solar plant having an absorber tube defining a longitudinal direction, a mirror array parallel to the longitudinal direction as a secondary concentrator for the concentration of light beams on the absorber tube, and a support frame for the receiver tube and the mirror array.
2. Description of Related Art
The generic receiver system is part of a solar power plant, which has, in addition, a primary concentrator in the form of a field of rows of mirrors mounted in parallel close to the ground, which concentrate solar rays onto the receiver system that are then projected once more by its mirror array, concentrated onto the absorber tube. For this purpose, the receiver system is found at a height of several meters above the primary-concentrator mirror array. Depending on the collector design in each case, such plants that are 4 m to 30 m high are known. The secondary concentrator has a suitable curve profile and projects the radiation downward onto the absorber tube disposed thereunder at the shortest possible distance. A heat-transfer fluid that is heated to several 100° C. by the concentrated light radiation passes through the absorber tube. The heat can be used, for example, for generating current or as process heat.
In the last several years, these types of Fresnel solar plants have been found in an accelerated phase of development. More recent documents on this subject are, for example, the article “Supernova—Construction, Control & Performance of Steam super heating linear Fresnel-Collector”, Gabriel Morin et al., Solar Paces Conference 2011, Book of Abstracts, and the Offenlegungsschriften (Unexamined Patent Applications) WO 2010/100293 A1 and WO 99/42765 A1.
For achieving a high efficiency, among other things, the optical geometric configuration of the mirrors and of the absorber tube is a basic prerequisite, in addition to the surface quality of the optical components of the mirror and of the absorber tube, which has been the subject of numerous inventions. The present subject of the invention thus particularly addresses the adjustment of the mirror array and of the receiver tube, which has been given little attention in the past.
The receiver system is subjected in part to very high and overall very different temperature fluctuations and environmental influences over a daily cycle.
The object of the invention is to configure the solar plant by an improved construction to be less sensitive to temperature fluctuations and environmental influences and thus finally also to increase its efficiency and service life.